archname is the archname string and is in the ByteLoader up to 0.06 checked strictly. Starting with ByteLoader 0.06_05 platform compatibility is implemented by checking the $archflag, and doing byteorder swapping for same length longsize, and adjusting the ivsize and ptrsize.

blversion is the ByteLoader version from the header as string. Up to ByteLoader 0.06 this version must have matched exactly, since 0.07 earlier ByteLoader versions are also accepted in the ByteLoader.

ivsize matches $Config{ivsize} of the assembling perl. A number, 4 or 8 only supported.

ptrsize matches $Config{ptrsize} of the assembling perl. A number, 4 or 8 only supported.

longsize is $Config{longsize} of the assembling perl. A number, 4 or 8. Only since blversion 0.06_03.

byteorder is a string of "0x12345678" on big-endian or "0x78563412" (?) on little-endian machines. The beginning "0x" is stripped for compatibility with intermediate ByteLoader versions, i.e. 5.6.1 to 5.8.0, Added with blversion 0.06_03, and also with blversion 0.04. See BcVersions

archflag is a bitmask of opcode platform-dependencies. Currently used: bit 1 for USE_ITHREADS bit 2 for MULTIPLICITY Added with blversion 0.06_05.

perlversion $] of the perl which produced this bytecode as string. Added with blversion 0.06_06.